Released on October 15, 1973 as part of Mystery to Me, “Hypnotized” became an album-rock radio staple even as it helped make the final argument for Fleetwood Mac’s move into pop music.

Bob Welch’s dreamscape journey across an majestic, unknowable landscape — delivered vocally with a whispery detachment — unfurls amid an insistent conversation on the hi-hat from Fleetwood and this thrilling series of jazz-inflected guitar fourths. Sound familiar?

Much has been made, and justifiably so, of the arrival of Lindsey Buckingham and Stevie Nicks — but “Hypnotized” illustrates how far Fleetwood Mac had come toward their polyester-era California singer-songwriter style in the era before that duo joined.

True, “Hypnotized,” with its dreamy AM-era sexuality and garrulous, riffy guitar soloing, is only just getting the hang of the success that would follow — but it’s the most complete portion of the bridge between Fleetwood Mac’s first and second hit-making periods.

Fleetwood Mac continued to evolve. Mystery to Me would be the final album to feature Bob Weston as guitarist and songwriter; Welch’s departure in 1974 then opened the door for Lindsey Buckingham and Stevie Nicks. Weston later worked with Murray Head and Steve Marriott’s All-Stars Band, while Welch had his own subsequent solo hit with “Sentimental Lady” – which was originally featured on Fleetwood Mac’s Bare Trees in 1972.

Still, as Bob Weston’s Wes Montgomery-isms are surrounded by a swirling, sometimes wordless breeze of voices from Bob Welch and Christine McVie on “Hypnotized,” it’s easy to see — just over the next horizon, after a few more personnel switches — Fleetwood Mac’s charttopping promised land.

Nick DeRiso has written for USA Today, American Songwriter, All About Jazz, and a host of others. Honored as columnist of the year five times by the Associated Press, Louisiana Press Association and Louisiana Sports Writers Association, he oversaw a daily section named Top 10 in the U.S. by the AP before co-founding Something Else! Nick is now associate editor of Ultimate Classic Rock.